SOFIA (Reuters) – A Bulgarian Roma couple are the biological parents of a 4-year-old blonde girl found in a Roma camp in Greece last week, DNA tests showed on Friday, solving a mystery that had captured global attention.

Bulgarian prosecutors are investigating whether the mother, Sasha Ruseva, 35, agreed to sell her child in Greece. Ruseva denies this, saying she left a 7-month old baby in Greece – where she worked as an olive-picker – in 2009 because she could not look after the child and needed to return to Bulgaria.

The case has come to illustrate the plight of Roma gypsies in Bulgaria, many of whom have spent their lives in poverty, are illiterate and have been marginalized by society.

The four-year-old, called Maria and dubbed the “blonde angel” by Greek media, was found last week hiding under a blanket at a Roma settlement in central Greece. DNA tests showed the Roma couple she was with were not her real parents.

Maria, whose case has reminded some of the disappearance of 3-year-old Briton Madeleine McCann in Portugal in 2007, is being looked after by a Greek charity, which says it has received over 10,000 calls with leads or from parents of missing children.

Thousands of calls poured in from as far as the United States to Sweden with leads on Maria’s possible identity, with the search narrowing to a poverty-stricken Bulgarian Roma couple – Sasha Ruseva and her husband, Atanas Rusev – this week.

Ruseva and her 37-year-old husband, parents of nine other children aged between 2 and 20, live in extreme poverty in a ramshackle house with a mud floor and partially finished roof in the town of Nikolaevo, some 280 km east from Sofia.

“We all live in one room – my husband, I and all the kids,” Ruseva told reporters late on Thursday, holding her naked two-year-old boy Atanas.

There are an estimated 10 million Roma living across Europe, and they are one of its oldest minorities. The Council of Europe, which monitors human rights, says they are also the most discriminated-against.